First base station managing a neighboring condition and cell area operation of a cell area, and system for managing a neighboring condition and cell area operation of a cell area

ABSTRACT

The present invention concerns a first base station managing a neighboring condition and cell area operation of a cell area, the cell area being a cell area of a wireless cellular network, the wireless cellular network comprising a telecommunication network enabling a transfer of information between the first base station and a second base station, where the wireless cellular network comprises a server linked to the telecommunication network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application of, and claims thebenefit of priority under 35 U.S.C. §120 from, U.S. application Ser. No.12/876,792, filed Sep. 7, 2010 now U.S. Pat. No. 8,095,136, which is adivisional of U.S. application Ser. No. 11/524,186, filed Sep. 21, 2006now U.S. Pat. No. 8,073,445, both of the above applications are hereinincorporated by reference, which claims the benefit of priority under 35U.S.C. §119 from European Patent Application No. 05 292163.2, filed Oct.13, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of thedetermination if a first cell of a wireless cellular network managed bya first base station in neighbour of a second cell of the wirelesscellular network managed by a second base station.

2. Description of the Related Art

Current wireless cellular networks are based on a centralisedarchitecture. A base station controller controls multiple base station,which in turn aim at covering, given cells. When a cellular wirelessmobile network operator wishes to add a cell in its network, it usuallyachieves the following operations. First, it installs the base stationon the site and connects it physically to its serving base stationcontroller. Then, it configures the base station controller so that basestation controller configures the base station with its operation domainsuch as the frequency of time slots or codes used for its operations.

In addition, the base station controller handles the handover proceduresof mobile terminals from/to newly added cell to/from existingneighbouring cells, so that mobile terminals wandering in an area servedby such cell can continue their communications seamlessly while movingfrom one cell to another.

In order to enable handover procedure, the base station controller hasto be aware of neighbouring conditions between the newly added cell andexisting cells. Usually, such determination of neighbouring conditionsis defined according to radio network planning techniques.

Radio network planning is classically determined by simulation methods.Prior to installing a base station on a given site, the cells that wouldbe the neighbouring cells of this newly introduced cell are determined.Such simulation methods usually require a fine knowledge of antennatype, position and steering used to operate each cell, as well asinformation related to radio wave propagation in the vicinity of thecell.

Such techniques are adapted for centralized wireless cellular networksor to wireless cellular networks which doesn't evolve a lot in the time.If the number of base stations which have to be added is ratherimportant, or if one or several base stations need to be moved from onelocation to another one or if some base stations are powered offperiodically, as for maintenance purpose, such techniques are notefficient.

SUMMARY OF THE INVENTION

The present invention relates generally to the field of thedetermination neighboring condition and cell area operation of a cellarea managed by a base station.

The aim of the invention is therefore to propose a device, a server anda system which allows to determine, in a distributed wireless cellularnetwork, the cell operation domain of a cell or cells managed by a basestation.

To that end, the present invention concerns a first base stationmanaging a neighboring condition and cell area operation of a cell area,the cell area being a cell area of a wireless cellular network, thewireless cellular network comprising a telecommunication networkenabling a transfer of information between the first base station and asecond base station, where the wireless cellular network comprises aserver linked to the telecommunication network. The base stationincludes a first unit that receives, at the first base station and fromthe server, information identifying the second base station in thetelecommunication network, the information identifying the second basestation being used for establishing a connection between the first andsecond base stations, a second unit that establishes a direct connectionbetween the first base station and the second base station through thetelecommunication network based on the information identifying thesecond base station received by the first unit, a third unit thatreceives, at the first base station, information representative of anoperation domain of a second cell area managed by the second basestation, a fourth unit that selects, at the first base station, anoperation domain of a first cell area managed by the first base stationbased on the information representative of the operation domain of thesecond cell area.

According to a particular feature, the first base station includes afifth unit that releases the connection between the first base stationand the second base station.

According to a particular feature, in the first base station the fifthunit selects whether the connection between the first base station andthe second base station is ready to be released before releasing theconnection between the first base station and the second base station.

According to a particular feature, in the first base station, theinformation representative of operation domain of the first cell areacomprises a parameter used for performance of appropriate operation insaid first base station.

According to a particular feature, the information representative ofoperation domain of the first cell area comprises at least a parametercorresponding to one of frequencies, time slots, and codes used foroperations in said first base station.

According to a particular feature, the first base station includes asixth unit that sends, from the first base station to the second basestation, information representative of the operation domain of the firstcell area managed by the first base station.

The present invention concerns a first base station managing aneighboring condition and cell area operation of a cell area, the cellarea being a cell area of a wireless cellular network. the wirelesscellular network comprising a telecommunication network enabling atransfer of information between the base station and a second basestation, wherein the wireless cellular network comprises a server linkedto the telecommunication network. The first base station includes afirst unit that establishes a direct connection between the first basestation and the second base station through telecommunication networkbased on the information identifying the second base station, a secondunit that receives, at the first base station, informationrepresentative of an operation domain of a second cell area managed bythe second base station, and a third unit that selects, at the firstbase station, an operation domain of a first cell area managed by thefirst base station based on the information representative of theoperation domain of the second cell area.

The present invention concerns also a system for managing a neighboringcondition and cell area operation of a cell area, the cell area being acell area of a wireless cellular network, the wireless cellular networkcomprising a telecommunication network enabling a transfer ofinformation between a first base station and a second base station ofthe system, where the wireless cellular network comprises a serverlinked to the telecommunication network. The system includes a firstbase station and a second base station. The first base station includesa first unit that receives, at the first base station and from theserver, information identifying the second base station in thetelecommunication network, the information identifying the second basestation being used for establishing a connection between the first andsecond base stations, a second unit that establishes a direct connectionbetween the first base station and the second base station through thetelecommunication network based on the information identifying thesecond base station received by the first unit, a third unit thatreceives, at the first base station, information representative of anoperation domain of a second cell area managed by the second basestation, and a fourth unit that selects, at the first base station, anoperation domain of a first cell area managed by the first base stationbased on the information representative of the operation domain of thesecond cell area. The second base station includes a fifth unit thatsends, to the server, information identifying the second base station inthe telecommunication network, the information identifying the secondbase station being used for establishing the connection between thefirst and second base stations, and a sixth unit that sends, to thefirst base station via the established connection, informationrepresentative of the operation domain of the second cell area managedby the second base station.

According to a particular feature in the system, the first base stationincludes a seventh unit that releases the connection between the firstbase station and the second base station.

According to a particular feature, in the system, the first base stationincludes an eighth unit that sends, from the first base station to thesecond base station, information representative of the operation domainof the first cell area managed by the first base station.

According to a particular feature, in the system, the second basestation includes a ninth unit that receives, from the first basestation, information representative of the operation domain of the firstcell area managed by the first base station.

According to a particular feature, in the system, the informationrepresentative of operation domain of the first cell area comprises aparameter used for performance of appropriate operation in said firstbase station.

According to a particular feature, in the system, the informationrepresentative of operation domain of the first cell area comprises atleast a parameter corresponding to one of frequencies, time slots, andcodes used for operations in said first base station.

The present invention concerns also a system for managing a neighboringcondition and cell area operation of a cell area, the cell area being acell area of a wireless cellular network, the wireless cellular networkcomprising a telecommunication network enabling a transfer ofinformation between a first base station and a second base station ofthe system, wherein the wireless cellular network comprises a serverlinked to the telecommunication network. The system includes a firstbase station and a second base station. The first base station includesa first unit that establishes a direct connection between the first basestation and the second base station through the telecommunicationnetwork based on the information identifying the second base stationreceived by the first unit, a second unit that receives, at the firstbase station, information representative of an operation domain of asecond cell area managed by the second base station, and a third unitthat selects, at the first base station, an operation domain of a firstcell area managed by the first base station based on the informationrepresentative of the operation domain of the second cell area. Thesecond base station includes a fourth unit configured to send, to thefirst base station via the established connection, informationrepresentative of the operation domain of the second cell area managedby the second base station.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics of the invention will emerge more clearly from areading of the following description of an example embodiment, the saiddescription being produced with reference to the accompanying drawings,among which:

FIG. 1 is a diagram representing the architecture of the wirelesscellular network according to the present invention;

FIG. 2 is a diagram representing the architecture of a server accordingto the present invention;

FIG. 3 is a diagram representing the architecture of a base stationaccording to the present invention;

FIG. 4 is an algorithm executed by a base station when it is installedin the wireless cellular network according to the present invention;

FIG. 5 is an algorithm executed by the server when a base station isinstalled in the wireless cellular network according to the presentinvention; and

FIG. 6 is algorithm executed by a neighbouring base station of a basestation installed in the wireless cellular network according to thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a diagram representing the architecture of the wirelesscellular network according to the present invention.

In the wireless cellular network of the FIG. 1, several base stations 10a, 10 b, 10 c and 10 d are linked each other through a telecommunicationnetwork 50. The base stations 10 a to 10 d access through the sametelecommunication network 50 to services provided by a server 20.

Each base station 10 a to 10 d is in charge of at least one cell 15where in mobile terminals 30 which are located within that cell 15 candetect a pilot signal and establish or receive some communicationsthrough the base stations 10 which manage the cells 15.

In the FIG. 1, only one cell 15 a, 15 b and 15 d is shown respectivelyfor each of the base stations 10 a, 10 b and 10 d, but we can understandthat a more important number of cells are managed by a base station 10in the present invention.

A cell 15 may be defined as a set of geographical locations to which agiven base station 10 provides the best quality of received pilotsignals by the mobile terminals 30 comprised in that cell 15 among pilotsignals of other neighbouring cells 15.

For the sake of simplicity, the cell managed by the base station 10 c isnot shown in the FIG. 1.

In the FIG. 1, only four base stations 10 a to 10 d are shown, but wecan understand that a more important number of base stations 10 can beused in the present invention. On a similar way, only one server 20 isshown, but we can understand that a more important number of servers canbe used in the present invention.

The server 20 stores information about all the base stations 10 a to 10d which are linked to the telecommunication network 50. Theseinformation are information representative of the geographical locationof the different base stations 10 a to 10 d, the International BaseSubscriber Identifier of each of the base station 10. With suchinformation, the server 20 is able to determine which given base station10 of the base stations 10 a to 10 d is geographically neighbour to agiven base station 10.

The telecommunication network 50 is a dedicated wired network or apublic network like a public switched network or an IP based network ora wireless network or a combination of above cited networks.

The telecommunication network 50 connects the base stations 10 and theserver 20 together and allows the transfer of messages between the basestations 10 and between each base station 10 and the server 20 accordingto the present invention.

Each base station 10 is connected to the telecommunication network 50through at least one link. Preferably, each base station 10 is connectedto the telecommunication network 50 through at least two links.

Such links are more preferably physical or logical access ports. Anaccess port allows the transfer of information between two base stations10 a to 10 b.

The base station 10 a has two access ports noted P10 a 1 and P10 a 2,the base station 10 b has two access ports noted P10 b 1 and P10 b 2,the base station 10 c has two access ports noted P10 c 1 and P10 c 2 andthe base station 10 d has two access ports noted P10 d 1 and P10 d 2.

For the sake of simplicity, only two access ports are shown in the Fig.for each of the base stations 10 a to 10 d, but we can understand that amore important number of access ports are used in the present invention.

The general principal of the present invention is that the wirelesstelecommunication network is built from interconnected base stations 10,which can individually serve multiple cells 15. When a new base station10, as example the base station 10 b is added to the wirelesstelecommunication network, such base station 10 b connects itself to theserver 20 and declares to the server 20 the list of access ports P10 b 1and P10 b 2 to be used for further communication with the other basestations 10.

For such newly added base station 10 b, the server 20 determines a largelist of neighbouring base stations 10 that are assumed, according to afirst criterion, to be neighbours to the base station 10 b. Such firstcriterion is as example based on the distance which separates the basestations 10. More precisely, a base station 10 is neighbour of anotherbase station 10 if the distance which separates the base stations 10 isbelow a predetermined distance. When two base stations 10 areneighbours, the cells 15 they are managing respectively can beconsidered as potential neighbouring cells.

Such list of neighbouring base stations 10 is transmitted back to thebase station 10 b, together with the address and at least an access portidentifier of each the neighbouring base station 10.

The server 20 transmits a list comprising the address and access portsnumber of the neighbour base stations 10 a and 10 d according to thefirst criterion to the base station 10 b.

Then, the base station 10 b establishes some permanent physical orlogical connection with its neighbour base stations 10 a and 10 d.

The connection between the base stations 10 a and 10 b is noted Co1 inthe FIG. 1 and is made through the links P10 a 1 and P10 b 1.

The connection between the base stations 10 b and 10 c is noted Co2 inthe FIG. 1 and is made through the links P10 b 2 and P10 b 2.

Once the inter-base station 10 connection is ready, the base station 10b retrieves some information related to the operation domain used by theinvolved neighbour cells managed by neighbour base stations 10 such asfrequency, time slot, codes . . . .

From this information, the base station 10 b decides on its own, of anacceptable operation domain for its own cell 15 b and then informs itsneighbouring base stations 10 a and 10 d that it starts operation of itsradio cell 15 b on the selected operation domain. The base stations 10 aand 10 d then add the new cell 15 b in their individual neighbouringcells lists for broadcasting, so that the mobiles terminals 30 served bytheir respective cells 15 a and 15 d can now measure the signals of thenewly added cell 15 b in order to proceed, if necessary, to handoverprocedure with the newly added cell 15 b. On its side, the base station10 b starts to broadcast in its cell 15 b, for the same reason, theneighbouring cells list of cell 15 b.

After some given time, the base station 10 b checks whether or not thecells 15 a, 15 d of its neighbouring base stations 10 a and 10 d areneighbours of its cell 15 b according to a second criteria, which isdifferent from the first one. Such second criteria is, as example,representative of the quantity of information transferred through eachof the connections Co1 and Co2 used for establishing handovers betweenits cells 15 b and the potential neighbours cells 15 a or 15 d.

The base station 10 b decides that a given cell 15 a is no longer aneighbour to its cell 15 b, when it determines that the quantity ofinformation in relation to handover across cells 15 a and 15 b, asobserved across connection Co1, is marginal with respect to its ownactivity. In such case, the base station 10 b reconfigures theneighbouring cells list broadcasted in cell 15 b, so that mobileterminals 30 located in cell 15 b no longer make measurements on cell 15a in order to prepare handover.

Similarly, under such occasion, the base station 10 a may decideautonomously to remove any cell 15 b from the neighbouring cells list ofany of its cell 15 a.

The base station 10 b initiates a base station disconnection procedurewith one of its neighbouring base stations 10 a and 10 d, when itdetermines that the activity of the connection with a base station 10 ismarginal with respect to its own activity. In such case, the basestation 10 b stops the connection with the base station 10. If that basestation 10 is the base station 10 d, the connection Co2 is then releasedand the associated access ports becomes available at both base stations10 b and 10 d for further connection to some other base stations 10. Tothat end, the releasing base station 10 b informs the server 20 that itsaccess port P10 b 2 is now available, and that it is no longer connectedto the base station 10 d via the access port P10 d 2.

The neighbouring cells lists for the cells of base station 10 b and 10 dare updated accordingly.

Then, the neighbouring cells lists converge to a restricted number ofneighbours.

In case of handover procedure, the communication contexts of the mobileterminals 30 are then exchanged across base stations 10 a and 10 b, 10 band 10 d via the connections Co1 and Co2.

It has to be noted here that, the general principle of the presentinvention is disclosed in an example wherein each base station 10manages one cell 15. When a base station 10 manages plural cells 15, thesame process is executed for each of the cells 15 managed by the basestation 10.

FIG. 2 is a diagram representing the architecture of a server accordingto the present invention.

The server 20 has, for example, an architecture based on componentsconnected together by a bus 201 and a processor 200 controlled byprograms as disclosed in the FIG. 5.

The bus 201 links the processor 200 to a read only memory ROM 202, arandom access memory RAM 203, a telecommunication network interface 206and a data base 204.

The memory 203 contains registers intended to receive variables, and theinstructions of the programs related to the algorithm as disclosed inthe FIG. 5.

The processor 200 executes the algorithm as disclosed in the FIG. 5.

The read only memory 202 contains instructions of the programs relatedto the algorithm as disclosed in the FIG. 5 which are transferred, whenthe server 20 is powered on to the random access memory 203.

The server 20 is connected to the telecommunication network 50 throughthe network interface 206. As example, the network interface 206 is aDSL (Digital Subscriber Line) modem, or an ISDN (Integrated ServicesDigital Network) interface, or PLC (Power Line Communication) interface,or a wireless interface, etc. Through such interface, the server 20transfers information to the base stations 10 as it will be disclosed inreference to the FIG. 5.

The database 204 comprises all information related to the bases stations10 like information representative of their geographical location, theInternational Base Subscriber Identifier of each of the base station 10,the available access ports of the base stations 10.

FIG. 3 is a diagram representing the architecture of a base stationaccording to the present invention.

The base station 10 has, for example, an architecture based oncomponents connected together by a bus 301 and a processor 300controlled by programs as disclosed in the FIGS. 4 and 6.

The bus 301 links the processor 300 to a read only memory ROM 302, arandom access memory RAM 303, a network interface 304 and a wirelessinterface 306.

The memory 303 contains registers intended to receive variables, thelist of neighbouring base stations, the neighbouring cells list of itscell 15, the operation domain of each of the neighbouring cells 15 andthe instructions of the programs related to the algorithms as disclosedin the FIGS. 4 and 6.

The processor 300 controls the operation of the network interface 304and the wireless interface 306.

The read only memory 302, contains instructions of the programs relatedto the algorithms as disclosed in the FIGS. 4 and 6 which aretransferred, when the base station 10 is powered on to the random accessmemory 303.

A base station 10 is connected to the telecommunication network 50through the network interface 304. As example, the network interface 304is a DSL, (Digital Subscriber Line) modem, or an ISDN (IntegratedServices Digital Network) interface, or PLC (Power Line Communication)interface, or a wireless interface, etc. Through such interface, thebase station 10 exchanges information which the server 20 and theneighbour base stations 10 which manage potential neighbouring cells 15.

The network interface 304 comprises several access ports. Each accessport is used for a dedicated connection with a base station 10 whichmanages at least one neighbouring cell 15. It has to be noted here thatone common access port can be dedicated for the negotiation with unknownbase stations of a given access port which will be used latter for theconnection. Another specific access port can be dedicated for thesignalling with the server 20.

The wireless interface 306 allows to communicate with the mobileterminals 30 which are in the cells 15 of the base station 10. Thewireless interface 306 contains one radio antenna or multiple radioantennas, each radio antenna serving a given cell 15 of base station 10.

FIG. 4 is an algorithm executed by a base station when it is installedin the wireless cellular network according to the present invention.

Such algorithm is, as example, executed by the processor 300 of a basestation 10 when it is installed and connected to the telecommunicationnetwork 50 or when it is powered on or when it is moved from onelocation to another one.

At step S400, the processor 300 obtains information representative ofthe location of the base station 10. Such information is obtained, asexample and in a non limitative way, from the person who installs thebase station 10 through a man machine interface not shown in the FIG. 3or through a Global Positioning System (GPS) device included within thebase station 10 or connected to it. As example and in a non limitativeway, the information representative of the location of the base station10 is the post address of the building wherein the base station 10 islocated, the phone number allocated to a telephone line within thebuilding wherein the base station 10 is located or any other networkaddress which permits to retrieve the post address of the buildingwherein the base station 10 b is located, or the GPS coordinates of thebase station 10 or the latitude, longitude and altitude of the positionof the base station 10.

The information representative of the location of the base station 10can be also the amplitude of signals and identifiers of base stations 10comprised in that signals, which are transmitted by some base stations10 in their respective cells 15 and received by the base station 10 orby a device connected to the base station 10.

At step S401, the processor 300 commands the transfer of a registrationmessage to the server 20. The registration message comprises theinformation representative of the location of the base station 10previously obtained, the telecommunication network address of the basestation 10 and the identifier of each of its access, ports. As example,if the base station 10 is the base station 10 b, the processor 300commands the transfer of the network address of the base station 10 band the identifiers of the access ports P10 b 1 and P10 b 2 of the basestation 10 b. In a variant of realization, the base station 10 btransfers only the identifier of an access port P10 b 1 or P10 b 2 whichhas to be used for the negotiation of further connections or for theinitialization of further connections with some other base stations 10.In another variant of realization, the base station 10 b also transfersthe identifier of one access port P10 b 1 or P10 b 2 which is dedicatedto communication with the server 20.

At next step S402, the processor 300 receives a response message fromthe server 20 through the telecommunication network 50. The responsemessage comprises the list of neighbouring base stations 10 determinedby the server 20 according to the first criterion. The list ofneighbouring base stations 10 comprises the addresses, within thetelecommunication network 50, of the base stations 10 which areneighbours of the base station 10 b according to the first criterion.According to the example of the FIG. 1 the list comprises the addressesof the base station 10 a and 10 d.

More precisely, the list of neighbouring base stations 10 comprisesalso, for each of the base stations 10 a and 10 d which are neighboursof the base station 10 b, the identifier of at least one access portavailable for future connection.

At next step S403, the processor 300 establishes connections with atleast some of the base stations 10 which are comprised in the list ofneighbouring base stations.

More precisely, if the number of available access ports of the basestation 10 b is smaller than the number of the base stations 10comprised in the list of neighbouring base stations, the processor 300establishes connections with a subset of its neighbouring base stations10 and memorizes the remaining part in the RAM memory 303.

A connection is established through the telecommunication network 50between two bases stations 10 by reserving an access port of each of thebase station 10 through which, a permanent signalling logical connectionis established between the two base stations 10. Such access portreservation can be made, in a variant, during a negotiation phasethrough a common access port, dedicated to the negotiation of accessports. Preferably, no more than one connection is established betweentwo base stations 10, even though these base stations 10 may involveneighbouring conditions between more than two of their cells 15.

The logical connection can be as example and in a non limitative way,compatible with the TCP (Transmission Control Protocol) or the UDP (UserDatagram Protocol) protocol, to be used on top of IP signalling.

Each base station 10 allocates a unique identifier to each connection.Such identifier is the identifier of the access port or the access portnumber. The combination of an access port number and the IP address of abase station 10 form then a unique socket. The IP address is used toidentify a base station 10, and the access port number identifies theconnection itself.

So, when the base station 10 b establishes a bi-directional signallingconnection with another base station 10, as example the base station 10a, it sends its messages together with its IP address, the IP address ofthe base station 10 a, the identifier of the access port it has reservedfor that connection and with an identifier of an access port that isstill available at the base station 10 a. Similarly, the base station 10a addresses the base station 10 b with the IP address of the basestation 10 b and with the access port identifier received from the basestation 10 b.

In another implementation mode of the invention, all the base stations10 use the same single fixed access port for the purpose of commonsignalling between base stations 10. The signals exchanged between thebase stations 10 over that access port carry the identification of theemitting base station 10 but later, a connection is established throughnegotiated access port.

A first connection noted Co1 is then established between the basestation 10 b and the base station 10 a through their respective accessports P10 b 1 and P10 a 1. A second connection noted Co2 is thenestablished between the base station 10 b and the base station 10 dthrough their respective access ports P10 b 2 and P10 d 2.

At the same step, the processor 300 transfers a message to the server 20informing it that the access port of each successful connection is nowunavailable.

Through the respective established connections Co1 and Co2, at stepS404, the processor 300 obtains and stores in RAM memory 303 the list ofcells 15 a and 15 d managed by its neighbouring base station 10 a and 10d and the operation domain of cells 15 a and 15 d managed by itsneighbouring base station 10 a and 10 d.

The operation domain of a cell 15 managed by a base station 10comprises, as example and in a non limitative way, the frequencies usedby the base station 10 in its cell 15 and/or the time slots used by thebase station 10 in its cell 15 and/or the codes used by the base station10 in its cell 15.

Each neighbouring base station 10 transfers through the establishedconnection with the base station 10 b, the operation domain of its cell15.

At step S405, the processor 300 determines the operation domain of itscell 15 b.

For that, the processor 300 builds an occurrence table of usage amongcells 15 of neighbouring base stations 10 stored in RAM memory 303 atstep S404 of the operation domains it has received and stored in RAMmemory 303 at step S404.

The processor 300 selects for its cell 15 b the operation domain amongthose of smallest occurrence observed among the cells 15 of itsneighbouring base stations 10. When the base station 10 b controls morethan one cell 15 b, the table also includes the operation domain of itscells 15 b. Each time an operation domain is chosen for one cell 15 b,the table of usage of the operation domains is updated. Then, theoperation domain of subsequent cells 15 b is selected among those ofsmallest occurrence and not yet being selected for other cells 15 b.

Preferably, the processor 300 selects for its cell 15 b the operationdomain among those of smallest occurrence observed among only the cells15 of its neighbouring base stations 10 that are neighbour to cell 15 b.

In another yet preferred embodiment, the probability of selection of anoperation domain of a neighbouring cell 15 a of the cell 15 b is adecaying function of the monitored information quantifying theneighbourhood relationship between the cell 15 a and the cell 15 b, thatis collected in step S407.

At next step S406, the processor 300 transfers the operation domains ofthe cell 15 b back to its neighbouring base stations 10 a and 10 dthrough the respective connections Co1 and Co2, so that they canmaintain their own occurrence table of usage of the operation domains.

At next step S407, the processor 300 activates the monitoring of theinformation transferred through the connections Co1 and Co2 establishedat step S403.

The information monitored are, as example, the messages transferred toand/or received from a neighbouring base station 10 a which are relatedto handover procedures of mobiles terminals 30 comprised in theirrespective cells 15.

A handover procedure occurs when a mobile terminal 30 is incommunication with another telecommunication device through a given basestation 10 b in an initial cell 15 b and moves to a cell 15 a of aneighbouring base station 10 a. During the handover procedure, the givenbase station 10 b has to stop to serve the mobile terminal 30 and theneighbouring base station 10 a has to start to serve the mobile terminal30 enabling the continuation of the communication. During a softhandover procedure, the neighbouring base station 10 a has to start toserve the mobile terminal 30, while the given base station 10 b keepsserving the mobile terminal 30, enabling macro-diversity, and thesimultaneous continuation of the communication over multiple cells.

If an handover procedure is engaged by a mobile terminal 30, it meansthat the mobile terminal 30 receives pilot signals from the cell 15 awith a higher power strength than the one of the pilot signals of thecell 15 b while still being located in the initial cell 15 b, and thatthe cell 15 a is an effective neighbouring cell of the cell 15 b of thebase station 10 b. When a handover procedure between two base stations10 is realised, some specific signalling messages are exchanged betweenthe two base stations 10.

Using these information over numerous consecutive or parallel handoverprocedures involving more than one mobile terminal 30, it is possible,for the base station 10 b to determine which are, among the cells 15 ofits neighbouring base stations 10, the neighbouring cells of each of itscell 15 b.

As example, and in a non limitative way, each time a message related toa handover procedure from/to cell 15 b to/from cell 15 a managed by basestation 10 a is transferred through the connection Co1, the processor300 increments a counter associated to the neighbourhood between cell 15b and cell 15 a of base station 10 a. Each time a message related to ahandover procedure from/to cell 15 b to/from cell 15 d managed by basestation 10 d is transferred through the connection Co2, the processor300 increments a counter associated to the neighbourhood between cell 15b and cell 15 d of base station 10 a and 10 d.

As another example, each time a message related to a handover procedureis transferred trough the connection Co1, the processor 300 increments acounter associated to the connection Co1. Each time a message related toa handover procedure is transferred trough the connection Co2, theprocessor 300 increments a counter associated to the connection Co2.

At next step S408, the processor 300 determines if whether or not it hasto check if the cells 15 of its neighbouring base stations 10 are or notneighbouring cells of its cells according to the second criterion.

As example and in a non limitative way, the processor 300 determinesthat it has to check if the cells 15 of its neighbouring base stations10 are neighbouring cells of its cells according to the secondcriterion, after a predetermined time of operation of the base station10 b and/or periodically and/or when the amount of informationtransferred through the connections Co1 and Co2 reaches a predeterminedquantity.

If the processor 300 has to check if the cells 15 of its neighbouringbase stations 10 are neighbouring cells of its cells according to thesecond criterion, the processor 300 moves to step S409. In the opposite,the processor 300 moves to the step S420.

At step S420, the processor 300 checks whether or not it has received amessage from a neighbouring base station 10 informing it that theneighbouring base station 10 suppresses the connection with it.

If no message is received, the processor 300 returns to step S408.

If such message is received, the processor 300 moves to step S421.

At step S421, the processor 300 removes from the list of neighbouringbase stations, the base station 10 which sent message. The processor 300also removes from the neighbouring cells list of its served cell 15 b,the cell or cells 15 served by the base station 10 which sent themessage, and removes the operation domain of the cell or cell 15 servedby that base station 10 from the table of usage of the operationdomains.

At next step S422, the processor 300 transfers a message to the server20 informing it that the connection between the base station 10 b andthe other base station 10 which sent the message at step S408, is brokenand that the access port of that connection is now available for furtheraccess.

The processor 300 returns then to the step S405 in order to define a newoperation domain for its cell 15. As far as the operation domain of acell is defined according to the operation domains of the neighbouringcells and/or according to the monitored information collected at stepS407, it is interesting to conduct a new determination of an operationdomain for its cell.

It has to be noted here that, if the processor 300 has established atstep S403 connections with a subset of its neighbouring base stations10, the processor 300 moves to step S403, considers a base station 10 ofthe remaining part of base stations 10 memorized and in the RAM memory303 and continue the present algorithm.

At step S409, the processor 300 considers the first connection with oneof its potential neighbouring base stations 10. As example, theprocessor 300 considers the connection Co1.

At next step S410, the processor 300 checks whether or not, there issome activity on that connection, and updates the cell neighbouringconditions according to the monitored information.

For that, in one realisation mode of the invention, the processor 300reads the value of the counter associated to the connection underprocess. If the value of the counter is upper than a predeterminedthreshold, the processor 300 decides that there is some activity on thatconnection and moves to step S411. On the contrary, the processor 300moves to step S413.

It has to be noted here that in a variant of realization, the processor300 calculates the sum of the values of each of the counters associatedto the connections Co1 and Co2, divides the value of the counterassociated to the connection under process by the calculated sum andcompare it to a predetermined threshold.

In another realisation mode of the invention, the processor 300 readsthe value of the counter associated to the neighbourhood between eachcell 15 b of the base station 10 b and the each cell 15 a of the distantbase station 10 a. If the value of the counter is upper than a firstpredetermined threshold, and that cell 15 a is not yet part of theneighbouring cells list of cell 15 b, the cell 15 a is added to theneighbouring cells list of cell 15 b. If the value of the counter isbelow a second predetermined threshold, and that cell 15 a is part ofthe neighbouring cells list of cell 15 b, the cell 15 a is removed fromthe neighbouring cells list of cell 15 b. When this is done for allcells 15 b and 15 a, the processor 300 informs the wireless interface306 to start to broadcast the updated neighbouring cells list of thecell 15 b.

It has to be noted here that in a variant of realization, the processor300 calculates the sum of the values of each of the counters, dividesthe value of each of the counters associated to the connection underprocess by the calculated sum and compare it to a predeterminedthreshold.

At step S411, the processor 300 checks whether or not there are someother connections for which the activity has not been checked.

If there is at least one connection for which the activity has not beenchecked, the processor 300 moves to step S412, considers anotherconnection and returns to step S410.

If there is no more connection for which the activity has not beenchecked, the processor 300 returns to step S408.

At step S413, the processor 300 removes from the list of neighbouringbase stations, the base station 10 through which it is connected throughthe connection under process. The processor 300 also removes from theneighbouring cells list of its served cell 15, the cell served by thebase station 10 which it is connected through the connection underprocess and removes the operation domain of the cell served by that basestation 10 from the table of usage of the operation domains.

As far as the amount of handovers between the cells of two base stationsis limited or null, it means that, despite the base stations 10 areneighbours, their respective cells 15 can not be considered asneighbours according to the second criterion.

At next step S414, the processor 300 sends a message to the base station10 it is linked through the connection under process, informing it thatthe connection is suppressed and releases the access port of thatconnection.

At next step S415, the processor 300 transfers a message to the server20 informing it that the access port of that connection is nowavailable. Preferably, the processor 300 informs also the server thatthe access port of the neighbour base station 10 used for thatconnection is now available.

The processor 300 then returns to the step S405 in order to define a newoperation domain for its cell 15.

It has to be noted here that, if the processor 300 has established atstep S403 connections with a subset of its potentials neighbouring basestations 10, the processor 300 moves to step S403, considers a basestation 10 of the remaining part of base stations memorized and in theRAM memory 303 and executes the algorithm as already been explained.

FIG. 5 is an algorithm executed by the server when a base station is installed in the wireless cellular network according to the presentinvention.

The present algorithm is executed by the processor 200 of the server 20.

At step S500, the processor 200 checks whether or not a message isreceived from the network interface 206. As far as no message isreceived, the processor 200 executes the loop constituted by the stepS500.

If a message is received from the network interface 206, the processor200 stores the contents of the message in the RAM memory 203 and movesto step S503.

At step S503, the processor 200 checks whether or not the base station10 which sent the message has already accessed to the server 20. Forthat, the processor 200 checks whether or not a list of neighbouringbase stations has been created for the base station 10 or if thedatabase 204 comprises the list of the available access ports of thebase station 10.

If the base station 10 which sent the message has already accessed tothe server 20, the processor 200 moves to step S504. On the contrary,the processor 200 moves to step S507.

At step S507, the processor 200 determines, according to a firstcriterion, the neighbouring base stations 10 of the base station 10which sent the message.

The first criterion, is preferably the distance between the basestations geographical locations.

From information representative of the geographical location of the basestation 10 which was comprised in the received message, that was storedin RAM 203 at step S500, the processor 200 consults the database 204 anddetermines the set of base stations 10 that are in the vicinity of thatlocation, with a predetermined distance criterion or a distancecriterion chosen so as to find a given number of neighbouring basestations 10.

If the information representative of the location of the base station 10which sent the message is the post address of the building wherein thebase station 10 is located, the processor 200 determines from the postaddress, the latitude, longitude and altitude of the base station 10 anddetermines the set of base stations 10 that are in the vicinity of thatlocation.

If the information representative of the location of the base station 10which sent the message is the phone number allocated to a telephone linewithin the building wherein the base station 10 is located, theprocessor 200 determines from the phone number, a post address, and thenthe latitude, longitude and altitude of the base station 10 b anddetermines the set of base stations 10 that are in the vicinity of thatlocation.

If the information representative of the location of the base station 10which sent the message are the GPS coordinates of the base station 10 orthe latitude, longitude and altitude of the position of the base station10, the processor 200 determines the set of base stations 10 that are inthe vicinity of that location.

If the information representative of the location of the base station 10are the amplitude of the signals and identifiers measured by the basestation 10 which sent the message, the processor 200 determines fromsuch identified signals an estimation of the latitude, longitude andaltitude of the base station 10 and determines the set of base stations10 that are neighbour to that estimated location.

At next step S508, the processor 200 retrieves from the database 204,for each base station 10 which is in the vicinity of the base station 10which sent the message, its address within the telecommunication network50 and the identifier of at least one available access port. Theprocessor 200 then adds in the database 204, the informationrepresentative of the geographical location of the base station 10,which was comprised in the received message, the determined list ofneighbouring base station 10, with their address and the selectedavailable access port for each base station 10 comprised in thedetermined list. At next step S509, the processor 200 commands thetransfer, through the telecommunication network 50, to the base station10 which sent the message, of a response message which comprises thelist of neighbouring base stations 10.

The list of neighbouring base stations 10 contains the address of basestation 10 which sent the message, the address of each the base station10 which is in the vicinity of the base station 10 which sent themessage, the identifier of an available access port of each base station10 which is in the vicinity of the base station 10 which sent themessage.

Once the message is transferred, the processor 200 returns to the stepS500 and waits the reception of a new message to be processed.

If at step S503, the processor 20 determines that the base station 10which sent the message has already accessed to the server 20, theprocessor 200 moves to step S504.

At that step, the processor 200 checks whether or not the receivedmessage, stored in RAM 203 at step S500 is representative of theavailability status of an access port of a base station 10. Such messageis as the one transferred at steps S415 or S422 of the algorithm of theFIG. 4.

If the received message is representative of the availability status ofan access port of a base station 10, the processor 200 moves to stepS505 and updates in the database 204, the access port status in the listof access ports of the base station 10 which sent the message by markingit as available if the availability status indicates that the port isavailable, or by marking it as unavailable if the availability statusindicates that the port is unavailable. If an access port is marked asunavailable, the processor 200 removes the base station 10 which wasconnected, through that link, to the base station which sent themessage, from the list of neighbour base stations of the base station 10which sent the message.

The processor 200 returns to the step S500 and waits the reception of anew message to be processed.

If the received message is not representative of the availability statusof an access port of a base station 10, the processor 200 moves to stepS507 already described and continue the process of the message.

FIG. 6 is algorithm executed by a neighbouring base station of a basestation installed in the wireless cellular network according to thepresent invention.

At step S600, the processor 300 of the base station 10 a, as example,checks whether or not a message is received from the network interface304. As far as no message is received, the processor 300 executes theloop constituted by the step S600.

If a message is received from the network interface 304, as example fromthe base station 10 b, the processor 300 stores the message in the RAM203 and moves to step S603.

At step S603, the processor 300 checks whether or not the base station10 which sent the message is known or not by the processor 300. Forthat, the processor 300 checks whether or not the message has beenreceived from an already established connection.

If the base station 10 which sent the message is known, the processor300 moves to step S606. On the contrary, the processor 300 moves to stepS604.

At the step S604, the processor 300 proceeds to a connectionestablishment in response to the one as disclosed at step S403 of theFIG. 4.

At the same step and in a variant of realisation, the processor 300transfers a message to the server 20 informing it that the access portof that connection is now unavailable.

At next step S605, the processor 300 transfers the operation domains ofits cells 15 to the base station 10 which sent the message. Thenprocessor 300 then returns to step S600.

At step S606, the processor 300 checks if the received message is amessage informing the base station 10 that the connection between thebase station 10 and the base station 10 which sent the message isreleased.

If the message is not a connection release message, the message storedin the RAM 203 at step S600 comprises the operation domain of the cellor cells of the base station 10 which sent the message. The processor300 moves then to the step S607 and updates its occurrence table ofusage of the operation domains of the cells 15 of its neighbouring basestations 10.

After that, the processor 300 moves to step S611 which will be disclosedlatter.

If the message is a connection release message, the processor 300 movesto step S608.

At that step S608, the processor 300 removes from the list ofneighbouring base stations, the base station 10 which sent the message,removes from the occurrence table of usage of operation domains thecells served by the base station 10 which sent the message, removes theoperation domain of the cell of that base station 10 from the table ofusage of the operation domains and removes that cell from theneighbouring cells lists. For each cell being served by the base station10, the processor 300 indicates to the wireless interface 306 to startbroadcasting an updated neighbouring cells list.

At step S609, the processor 300 releases the connection with the basestation 10 which sent the message.

In a variant of realisation, the processor 300 transfers at step S610 amessage to the server 20 informing it that the access port used for thereleased connection is now available. The processor 300 then moves tostep S611.

At next step S611, the processor 300 determines the operation domain ofits cell 15 using the modified table of usage of the operation domains.

The processor 300 selects for its cell 15 the operation domain amongthose of smallest occurrence observed among the cells of itsneighbouring base stations 10. When the base station 10 controls morethan one cell, the table also includes the operation domain of all ofits cells 15. Each time an operation domain is chosen for one cell 15,the table of usage of the operation domain is updated. Then, theoperation domain of subsequent cells 15 is selected among those ofsmallest occurrence and not yet being selected for other cells 15.

In a preferred embodiment, the processor 300 selects for the cell 15 ofits base station 10, the operation domain among those of smallestoccurrence observed among only the cells 15 of its neighbouring basestations 10 that are neighbour to the cell 15 of its base station 10.

At next step S612, the processor 300 transfers the determined operationdomains of its cell 15 to all its neighbouring base stations 10 throughthe respective connections. Then, the processor 300 returns back to stepS600.

Naturally, many modifications can be made to the embodiments of theinvention described above without departing from the scope of thepresent invention.

1. A first base station managing a neighboring condition and cell areaoperation of a cell area, the cell area being a cell area of a wirelesscellular network, the wireless cellular network comprising atelecommunication network enabling a transfer of information between thefirst base station and a second base station, wherein the wirelesscellular network comprises a server linked to the telecommunicationnetwork, the first base station comprising: a first unit configured toreceive, at the first base station and from the server, informationidentifying the second base station in the telecommunication network,the information identifying the second base station being used forestablishing a connection between the first and second base stations; asecond unit configured to establish a direct connection between thefirst base station and the second base station through thetelecommunication network based on the information identifying thesecond base station received by the first unit; a third unit configuredto receive, at the first base station, information representative of anoperation domain of a second cell area managed by the second basestation; and a fourth unit configured to select, at the first basestation, an operation domain of a first cell area managed by the firstbase station based on the information representative of the operationdomain of the second cell area.
 2. The first base station according toclaim 1, further comprising: a fifth unit configured to release theconnection between the first base station and the second base station.3. The first base station according to claim 2, wherein the fifth unitis further configured to select whether the connection between the firstbase station and the second base station is ready to be released beforereleasing the connection between the first base station and the secondbase station.
 4. The first base station according to claim 1, whereinthe information representative of operation domain of the first cellarea comprises a parameter used for performance of appropriate operationin said first base station.
 5. The first base station according to claim4, wherein the information representative of operation domain of thefirst cell area comprises at least a parameter corresponding to one offrequencies, time slots, and codes used for operations in said firstbase station.
 6. The base station according to claim 1, furthercomprising: a sixth unit configured to send, from the first base stationto the second base station, information representative of the operationdomain of the first cell area managed by the first base station.
 7. Afirst base station managing a neighboring condition and cell areaoperation of a cell area, the cell area being a cell area of a wirelesscellular network, the wireless cellular network comprising atelecommunication network enabling a transfer of information between thefirst base station and a second base station, wherein the wirelesscellular network comprises a server linked to the telecommunicationnetwork, the first base station comprising: a first unit configured toestablish a direct connection between the first base station and thesecond base station through the telecommunication network based oninformation identifying the second base station; a second unitconfigured to receive, at the first base station, informationrepresentative of an operation domain of a second cell area managed bythe second base station; and a third unit configured to select, at thefirst base station, an operation domain of a first cell area managed bythe first base station based on the information representative of theoperation domain of the second cell area.
 8. A system for managing aneighboring condition and cell area operation of a cell area, the cellarea being a cell area of a wireless cellular network, the wirelesscellular network comprising a telecommunication network enabling atransfer of information between a first base station and a second basestation of the system, wherein the wireless cellular network comprises aserver linked to the telecommunication network, the system comprising:the first base station including: a first unit configured to receive, atthe first base station and from the server, information identifying thesecond base station in the telecommunication network, the informationidentifying the second base station being used for establishing aconnection between the first and second base stations, a second unitconfigured to establish a direct connection between the first basestation and the second base station through the telecommunicationnetwork based on the information identifying the second base stationreceived by the first unit, a third unit configured to receive, at thefirst base station, information representative of an operation domain ofa second cell area managed by the second base station, a fourth unitconfigured to select, at the first base station, an operation domain ofa first cell area managed by the first base station based on theinformation representative of the operation domain of the second cellarea, and the second base station including: a fifth unit configured tosend, to the server, information identifying the second base station inthe telecommunication network, the information identifying the secondbase station being used for establishing the connection between thefirst and second base stations, and a sixth unit configured to send, tothe first base station via the established connection, informationrepresentative of the operation domain of the second cell area managedby the second base station.
 9. The system according to claim 8, furthercomprising: a seventh unit configured to release the connection betweenthe first base station and the second base station.
 10. The systemaccording to claim 8, wherein the first base station further comprisesan eighth unit configured to send, from the first base station to thesecond base station, information representative of the operation domainof the first cell area managed by the first base station.
 11. The systemaccording to claim 8, wherein the second base station further comprisesa ninth unit configured to receive, from the first base station,information representative of the operation domain of the first cellarea managed by the first base station.
 12. The system according toclaim 10, wherein the information representative of operation domain ofthe first cell area comprises a parameter used for performance ofappropriate operation in said first base station.
 13. The systemaccording to claim 10, wherein the information representative ofoperation domain of the first cell area comprises at least a parametercorresponding to one of frequencies, time slots, and codes used foroperations in said first base station.
 14. A system for managing aneighboring condition and cell area operation of a cell area, the cellarea being a cell area of a wireless cellular network, the wirelesscellular network comprising a telecommunication network enabling atransfer of information between a first base station and a second basestation of the system, wherein the wireless cellular network comprises aserver linked to the telecommunication network, the system comprising:the first base station including: a first unit configured to establish adirect connection between the first base station and the second basestation through the telecommunication network based on informationidentifying the second base station, a second unit configured toreceive, at the first base station, information representative of anoperation domain of a second cell area managed by the second basestation, a third unit configured to select, at the first base station,an operation domain of a first cell area managed by the first basestation based on the information representative of the operation domainof the second cell area, and the second base station including: a fourthunit configured to send, to the first base station via the establishedconnection, information representative of the operation domain of thesecond cell area managed by the second base station.